Question

How many molecules are present in 1g of hydrogen gas?

Answer 1

we know that 2 grams of H₂ molecules contain 6.023 × 10²³ molecules

⇒ 1 gram of H₂ molecules contain 3.011 × 10²³ molecules

Answer 2

No of moles of 1 g of H2 gas is
2g contains 1 mol hence
1g will contain 1/2 moles of H2

Molecules = No.of moles× avagadro number
$0.5 \times 6.022 \times {10}^{23 } \\ = 3.011 \times {10}^{23}$